1. Field of the Invention
The present invention relates to a bonding member (material) for a semiconductor device, a semiconductor device using the bonding member, and a manufacturing method therefor and, more particularly, to a semiconductor device having high voltage resistance (a high-voltage semiconductor device, hereinafter).
2. Description of the Related Art
At present, for bonding inside a part and high heat-resistive bonding, high-Pb solder having a high melting point (solder containing a high level of lead) is used. In particular, in case of a high-voltage semiconductor device, heat resistant temperature of approximately 200° C. is required in a working environment of the high-voltage semiconductor device, so that the high-Pb solder having a solidus in the vicinity of 300° C., for example, a solder containing a high level of Pb (lead), such as 95Pb5Sn (a solidus line at 300° C. and a liquidus line at 314° C.), 98Pb2Sn (a solidus line at 316° C. and a liquidus line at 322° C.), 98Pb2Ag (a solidus line at 304° C. and a liquidus line 305° C.), 97.5Pb1.5Ag1Sn (a solidus line at 309° C. and a liquidus line 309° C.) or the like is used for bonding a semiconductor element.
As examples of such a high-voltage semiconductor device, there are a power semiconductor element, such as IGBT, diode, GTO, transistor or the like, and-a power semiconductor-module using them (hereinafter referred to as “semiconductor device” generically). These semiconductor devices are described in, for example, the following patent documents 1 to 5. Also, a new solder which is substituted for the above-mentioned high-Pb solder is discussed in the following non-patent document 1.
[Patent Document 1]
Japanese Patent Application Laid-Open No. Hei. 10-125856 (corresponding to EP 0828341 A2).
[Patent Document 2]
Japanese Patent Application Laid-Open No. Hei. 7-161877.
[Patent Document 3]
Japanese Patent Application Laid-Open No. 2002-142424.
[Patent Document 4]
Japanese Patent Application Laid-Open. No. 2002-261210.
[Patent Document 5]
Japanese Patent Application Laid-Open No. 2002-359328 (corresponding to US 2002/0140059 A1).
[Non-Patent Document 1]
John N. Lalena, Nancy F. Dean, and Martin W. Weiser; “Experimental Investigation of Ge-doped Bi-11Ag as a New Pb-Free Solder Alloy for Power Die Attachment”, Journal of ELECTRONIC MATERIALS, Vol. 31, No. 11, 2002, pages 1244-1249.